In recent years, it has been desired to develop clean energy because of global environmental problems and the like such as exhaustion of energy resources and an increase in CO2 in the atmosphere. In particular, photovoltaic power generation using solar cell modules has been developed, put to practical use and is progressing as a new energy source.
As a solar cell that configures such a solar cell module, a double surface electrode type solar cell has been conventionally a mainstream, in which a p-n junction is formed for example by diffusing impurities whose conductivity type is opposite to that of a monocrystalline or polycrystalline silicon substrate, over a light receiving surface of the silicon substrate, and electrodes are formed on the light receiving surface of the silicon substrate and a back surface opposite to the light receiving surface, respectively. In addition, development of a so-called back surface electrode type solar cell has been advanced in recent years, in which an electrode for the p type and an electrode for the n type are both formed on a back surface of a silicon substrate.
In addition, the thickness of the silicon substrate has also been reduced in order to reduce the cost of raw materials. There arises a problem, however, that reduction in the thickness of the solar cell due to reduction in the thickness of the silicon substrate results in a crack in the solar cell during the operation of wiring the solar cells when the solar cell module is fabricated.
In order to solve such a problem, for example, Japanese Patent Laying-Open No. 2005-340362 (Patent Document 1) describes a solar cell module electrically connecting solar cells by placing the solar cells on a wiring of a wiring substrate.
Patent Document 1: Japanese Patent Laying-Open No. 2005-340362